Lecture 5 Part 3 Flashcards
8 types of Sprayers
- Boom Sprayers
- Airblast Sparyers
- “jetpack Sprayers”
- Recovery Sprayers
- Cannon Sprayers
- Hand Sprayers
- Aerial Sprayers
- Powder Sprayers
5 types of Nozzles
- Flat fan (convex distribution (oval))
- Flat fan (even distribution (line))
- Cone (convex distribution (more inside, less outside)
- Cone (even distribution (filled in circle))
- Hollow Cone (concave distribution (circle))
Droplet size codes:
Extremely fine: XF (purple) less than 60 microns
to
Ultra Coarse : UC (black) greater than 650 microns
Droplet size and distribution, three factors to consider and how does the droplet size affect each factor?
- Coverage 2. Canopy Penetration 3. Drift Risk
XF: High Low High
UC: Low High Low
The Larger the Spray Droplet Size
The Less Distance the Droplet Drifts
Considerations for smaller droplets (3) and the main aim of having smaller droplets
The aim is to have better coverage
* More droplets in same volume of water
* Smaller droplets deposit (“stick”) on the
target better and are less likely to roll off
* More likely to drift
Considerations for bigger droplets (3) and the main aim of having bigger droplets
The aim is to reduce drift
* Fewer droplets in same volume of water
* Larger droplets don’t deposit (“stick”) on
the target as well and may roll off
* Less likely to drift
7 parameters for calibration and setting of sprayers
Distribution quality check
Distribution profile should follow the vegetation profile as much as possible
Use _______ to evaluate:
* distribution of the drops on
the external and internal
parts of the vegetation
* the penetration of the drops into the canopy
water-sensitive cards
What Is the most important factor in terms of weather conditions?
Wind: speed and direction
How does temperature and humidity play a role in when to spray?
High temperatures (>25C) and low humidity (<50%) increase the likelihood of drift due to the decrease in droplet size from evaporation.
Discuss the role that rain can play when applying a spray (3)
- Most chemicals require a rain free period after application, however some soil active chemicals can be sprayed in the rain (especially herbicides).
- Heavy or sustained rainfall or irrigation shortly after pesticide application can increase runoff, leaching, and volatilization.
- DO NOT apply pesticides if heavy rain is in the forecast!
What is Crop Adapted Spray (CAS)
A method to adapt dosage and/or spray volume to the crop size in order to always obtain equal deposit of pesticide independent of crop size
When discussing the reduction of doses what are the two main things that we studied?
- Crop adapted sprays
- VRT (Variable Rate Technologies)
